This invention relates to a continuous process for the recovery, including melting and casting, of used containers fabricated at least in part from different metals or alloys. More particularly, this invention relates to a continuous method or process for reclamation of used containers, such as beverage containers, in a manner which permits recovery or segregation of container components substantially in accordance with their compositions, for example, or composition types. In addition, the invention relates to the recovery of the component in accordance with its composition, melting, casting and fabricating the same into a container, for example, in a continuous manner for conserving energy.
In the packaging or container field, such as the used beverage containers having at least one or more components thereof fabricated from aluminum alloys, there has been ever-increasing interest and extensive research into methods of reclaiming the aluminum components. The interest has been precipitated by the importance of conserving resources and caring for environmental problems. However, heretofore recycling such materials has been greatly hampered by the lack of a method which is economically attractive. For example, attempts to recycle beverage cans having bodies fabricated from one aluminum alloy and tops or lids constructed from a different aluminum alloy often results in an aluminum melt having the composition of neither alloy. Such melt greatly decreases in value and utility because it does not readily lend itself to reuse in the can body or lid without major dilutions, purifications and realloying or other modifications. Thus, it can be seen that there is a great need for a method of recycling containers of the type, for example, described wherein the different components thereof are recovered and segregated according to alloy or according to alloy type.
The problem of segregation of different alloys is recognized in U.S. Pat. No. 3,736,896, where there is disclosed the separating of aluminum alloy tops or lids from steel bodied cans by melting a small band of aluminum around the periphery of the can body to provide a separating area allowing separation of the aluminum end from the steel cylindrical body. In this disclosure, induction heating is used to melt the band wherein an encircling inductor surrounds a bead and is connected to a high frequency power supply. However, this approach seems to presume that a used beverage can is not crushed and the end remains perfectly circular. Further, to melt the ends off in this manner would not seem to be economical since the ends would have to be removed individually.
In U.S. Pat. No. 4,016,003, containers having aluminum alloy bodies and lids are shredded to particles in the range of 1 to 11/2 inch and then subjected to temperatures of around 700.degree. F. to remove paints and lacquers. In addition, U.S. Pat. No. 4,269,632 indicates that since the conventional alloys for can ends, e.g., Aluminum Association (AA alloy) 5182, 5082 or 5052, and for can bodies, e.g., AA3004 or AA3003, differ significantly in composition, and in the manufactured can, the end and body are essentially inseparable, and that an economical recycle system requires the use of the entire can. U.S. Pat. No. 4,269,632 further notes that the recycling of cans results in a melt composition which differs significantly from the compositions of both the conventional can end and can body alloys. In this patent, it is suggested that both can end and body be fabricated from the same alloy to obviate the recycling problem. With respect to can ends and bodies made from AA5182 and 3004, it is indicated that normally pure aluminum must be added regardless of the alloy prepared.
In view of these problems with recycling metal containers, such as aluminum beverage containers having components thereof comprised of different alloys, it would be advantageous to have a method which would permit recovery of the containers by segregating the components on a continuous basis according to their alloys or segregating the components according to their alloy type. Additionally, it would be advantageous to continuously melt and cast the segregated component and refabricate it in accordance with normal procedures without, inter alia, expensive dilutions or purification steps.